POJ 1088 滑雪

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<algorithm>
#include<cstring>
#include <queue>
#include <vector>
#include<bitset>
#include<map>
#include<deque>
using namespace std;
typedef long long LL;
const int maxn = 1e4+5;
const int mod = 77200211+233;
typedef pair<int,int> pii;
#define X first
#define Y second
#define pb push_back
//#define mp make_pair
#define ms(a,b) memset(a,b,sizeof(a))
const int inf = 0x3f3f3f3f;
#define lson l,m,2*rt
#define rson m+1,r,2*rt+1
typedef long long ll;
#define N 100010
int r,c;
int dp[105][105];
int a[105][105];

int dx[4]={1,-1,0,0};
int dy[4]={0,0,1,-1};

int dfs(int x,int y){
    if(dp[x][y]) return dp[x][y];
    for(int i=0;i<4;i++){
        int tx=x+dx[i];
        int ty=y+dy[i];
        if(tx<1||tx>r||ty<1||ty>c) continue;
        if(a[x][y]>a[tx][ty]) dp[x][y]=max(dp[x][y],dfs(tx,ty)+1);
    }
    return dp[x][y];
}

int main(){
    while(~scanf("%d%d",&r,&c)){
        for(int i=1;i<=r;i++)
            for(int j=1;j<=c;j++)
                scanf("%d",&a[i][j]);
        ms(dp,0);
        int ans=-1;
        for(int i=1;i<=r;i++){
            for(int j=1;j<=c;j++){
                ans=max(ans,dfs(i,j));
            }
        }
        cout<<ans+1<<endl;
    }
    return 0;
}